Waterproof footwear

ABSTRACT

Waterproof footwear and methods for making the same. The footwear includes a laminate upper having at least a waterproof, water vapor permeable functional layer and an outer layer stitched to a strobel board to form a closed upper. A waterproof gasket material is adhered to the inner surface of the bottom of the closed upper.

FIELD OF THE INVENTION

[0001] The present invention relates to waterproof footwear and methods for making the same.

DESCRIPTION OF RELATED ART

[0002] Common footwear constructions, such as those used in boots or shoes, employ waterproof constructions comprising a liquid waterproof but water vapor permeable (i.e., breathable) layer as part of a lining between the wearer's foot and the exterior parts of the footwear. The waterproof, water vapor permeable material is referred to in the art as the “functional layer”. The functional layer is incorporated in a mult-layered lining fabric referred to as a waterproof, breathable fabric. Waterproof, breathable fabric panels are usually sewn together and sealed at the seams to form a waterproof liner within the footwear. One prior art embodiment of such a waterproof liner is called a bootie wherein the waterproof, breathable fabric essentially surrounds the foot completely. There also exists non-bootie waterproof, breathable fabric liner constructions other than a bootie wherein the lining fabric is sealed to other waterproof materials in the sole area, rather than having the fabric extend completely underfoot as in the bootie. In either case, the fabric panels which form the waterproof breathable liner are normally an interior part of the footwear with an outer textile layer of the fabric panel in contact with the inner surfaces of the footwear upper. The footwear upper is usually composed of leather, fabrics, etc. and additionally includes components such as eyelets, heel counters, steel safety toes, toe caps, etc.

[0003] The waterproof, breathable fabric panels of the liner are composed of multiple layers wherein the different layers may provide different functions, e.g., durability, waterproofness, fashion appeal, etc. In making the material for the panels of the liners, a thin functional layer is commonly laminated to at least one fabric layer, and often times laminated between fabric layers. Sometimes thin coatings on fabric are used as the functional layer instead of a membrane. The waterproof layer is typically thin and fragile. Thus, it is normally provided with at least an outermost protective fabric layer which is designed to provide durability and abrasion resistance between the thin functional layer and the footwear upper.

[0004] The above mentioned footwear constructions lead to several fabrication problems. For example, at least the outermost fabric of the laminate must be attached to (e.g., by stitching, gluing, etc.) the inner surfaces of the shoe upper. This, of course, introduces an additional manufacturing step to the already labor intensive process of producing footwear. Moreover, the attachment of the upper to the outermost fabric of the laminate also provides another area for the footwear to fail. For example, attachment of the laminate to the upper may fail over a course of use of the footwear. Moreover, the inclusion of the waterproof, breathable fabric panels in the footwear may cause sizing problems (i.e., depending on the method used to construct the footwear, utilization of waterproof, breathable fabric panels may cause the shoe to be somewhat smaller than originally sized). Thus, it can be appreciated that problems exist in making durable, waterproof footwear.

[0005] The current invention provides footwear and methods for making the same which provide durable, waterproof footwear which is simply made in a minimal number of steps. Moreover, since the footwear of the invention is of the “stitched” construction type, there is no need for the expensive, time consuming lasting equipment that is currently used in efforts to produce waterproof footwear.

SUMMARY OF THE INVENTION

[0006] The invention relates to novel waterproof footwear constructions of the stitched type (e.g., of the strobel stitched type) and methods for making the same.

[0007] The footwear comprises a laminate upper including at least a waterproof, water vapor permeable functional layer and an outer layer laminated thereto. The upper is stitched to a strobel board to form a closed upper having an inner surface, an outer surface, an open top, and a closed bottom. A waterproof gasket material is adhered to the inner surface of the closed bottom of the closed upper, covering the strobel board, the stitching and at least a perimeter edge of the upper.

[0008] A method for forming the novel footwear includes forming into the shape of an upper a laminate having at least a waterproof, water vapor permeable functional layer and an outer layer. Stitching the upper to a strobel board to form a closed upper having an inner surface, an outer surface, an open top, and a closed bottom. And adhereing a waterproof gasket material to the inner surface of the closed bottom of the closed upper, such that the waterproof gasket material covers the strobel board, the stitching and at least a perimeter edge of the upper.

DESCRIPTION OF THE DRAWINGS

[0009] The operation of the present invention should become apparent from the following description when considered in conjunction with the accompanying drawings, in which:

[0010]FIG. 1 is a cross-sectional view of a closed upper according to the invention.

[0011]FIG. 2 is a cross-sectional view of a waterproof footwear article according to the invention.

[0012]FIG. 3 is a top view of the inner surface of the bottom portion of a closed upper according to the invention.

[0013]FIG. 4 is a top view of the inner surface of the bottom portion of a waterproof footwear article according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0014] The novel footwear of the invention includes a laminate upper including at least a waterproof, water vapor permeable functional layer and an outer layer laminated thereto. The upper is stitched to a strobel board to form a closed upper having an inner surface, an outer surface, an open top, and a closed bottom.

[0015] The invention can best be described with reference to the non-limiting figures wherein FIG. 1 shows, in cross-section, a closed upper according to the invention. Footwear 1 includes laminate upper 2 stitched to strobel board 3 by stitching 4. Referring to FIG. 3, it can be seen that laminate upper 2 extends somewhat under to the bottom of the closed upper forming a perimeter edge.

[0016] Referring to FIG. 2, waterproof gasket material 6 is shown adhered to the inner surface of the closed bottom of the closed upper, covering the inner surface of the strobel board 3, the stitching 4, and at least a portion of the perimeter edge of the upper 2. FIG. 4 is a top view of the footwear wherein it can be seen that waterproof gasket material 6 covers the strobel board 3, the stitching 4, and the perimeter edge of the upper 2.

[0017] The laminate upper comprises at least two layers. One layer is a waterproof, water vapor permeable functional layer, such as a breathable polymeric membrane. As used herein “water vapor permeable” and “breathable” are used interchangeably and mean that the functional layer has a water vapor permeability coefficient Ret of less than 200 m² Pa W⁻¹. The water vapor permeability is tested by the Hohenstein skin model. This test method is described in DIN EN 31092 (02/94) or ISO 11092 (19/33). Breathable polymeric membranes may be breathable by virtue of pores in the breathable polymeric membrane or through a solution diffusion mechanism. Breathable polymeric membranes may be selected from, for example, the group consisting of fluoropolymers, polyurethanes, polyesters, polyethers, polyamides, polyacrylates, coplyether esters and copolyether amides. In an aspect of the invention, a water-impermeable, breathable polymeric membrane is a membrane of microporous polytetrafluoroethylene (PTFE), such as expanded PTFE as taught in, for example, U.S. Pat. Nos. 3,953,566 and 4,187,390 to Gore. The subject matter of these patents is hereby incorporated by reference.

[0018] The second layer of the laminate upper is laminated to the functional layer to serve as the outer layer of the footwear. Lamination is generally carried out with the use of a discontinuous pattern of suitable adhesive. Thus, water vapor permeability is not significantly effected. The outer layer can be a textile fabric or leather. Textile fabrics can be woven, knit, mesh, nonwoven, felt constructions, etc. Textiles can be produced from natural fibers such as cotton, or from synthetic fibers such as polyesters, polyamides, polypropylenes, polyolefins, or blends thereof. The outer layer is relatively durable, abrasion resistant and provides an aesthetically pleasing appearance.

[0019] To form the laminate into the shape of an upper, panels of the laminate material can be cut and assembled to the desired form. Pieces of laminate can be joined together by sewing, welding, gluing, etc. When pieces of laminate are sewn together the seams can be made waterproof by applying known seam sealing tape materials, such as GORE-SEAM® tape (available from W.L. Gore and Associates, Inc.), to the seam area. Moreover, other sealants may be applied to the seams to render them waterproof if they are not inherently waterproof due to welding or gluing.

[0020] Once formed into the desired shape of a footwear upper, the laminate upper can be stitched to a strobel board using, for example, the well known Strobel stitching machine to form a closed upper, illustrated in FIG. 1. Suitable materials which can be used as a strobel board are well known to the skilled artisan.

[0021] The waterproof gasket material can be any suitable waterproof material, which is generally formed into the shape of the bottom of a wearer's foot (or to the footwear bottom). Suitable waterproof gasket materials include, for example, polymeric materials, a polymeric containing material, waterproof fabrics (either woven or nonwoven), a textile material treated to make it waterproof, etc. In an aspect of the invention the gasket can be more than one layer. For example, the gasket can be a backer material (such as a nonwoven, knit, etc.) laminated or otherwise attached to a thin polyurethane film. On the opposite side of the polyurethane film could be provided a flowable adhesive which is capable of melting and flowing to form a bond and waterproof seal with the laminate upper. In any case, the waterproof gasket material is adhered to the inner surface of the bottom of the closed upper. The adhesive may be any suitable adhesive material. Non-limiting adhesives include, for example, polyurethane, natural latex rubber, nitrile rubber, silicone rubber, butyl rubber, fluorinated rubber, copolyether polyester, polyester, ethylene vinyl acetate or polyamide. In an aspect of the invention, the adhesive is a thermoplastic material. The adhesive can be applied to the surface of the strobel board and the perimeter edge of the upper, to the bottom surface of the waterproof gasket, or to the surface of the strobel board, the perimeter edge of the upper and to the bottom surface of the waterproof gasket. In an aspect of the invention, the waterproof gasket may be previously supplied with adhesive material (such as in the layered gasket material discussed above), which can be activated at the point of footwear assembly by application of heat, or heat and pressure. The adhesive need only be applied in such an amount and at selected locations to provide a waterproof seal between the gasket and the laminate upper. It is generally desirable, however, to provide adhesive such that the entire surface of the gasket which is in contact with the bottom of the closed upper is covered with adhesive.

[0022] To adhere the waterproof gasket material to the inner surface of the bottom of the closed upper the closed upper can be turned inside out and the gasket adhered to the bottom surface of the upper and then the upper returned to outside out configuration. In an alternative embodiment, the gasket can be slipped into the closed upper and adhered to the bottom of the closed upper. If pressure is used to accomplish adhesion, then a shoe last could be inserted into the closed upper to apply pressure to the gasket.

[0023] It may be desirable to provide the inner surface of the laminate upper with an inner liner material, either for aesthetics, for increased wearer comfort, or for increased durability. Such an inner liner material can be adhered or otherwise attached to the functional layer of the laminate upper. Suitable inner liner materials include, for example, the textile fabrics mentioned above.

[0024] Moreover, after the waterproof gasket is adhered to the inner surface of the closed bottom of the closed upper, any suitable foot bed can be inserted into the footwear to provide for improved wearer comfort, if desired. Suitable foot bed materials are well known to the skilled artisan and include, for example, ethylene vinyl acetate, felt, etc. Foot beds are usually easily inserted and/or removed from the footwear article and are, thus, replaceable. Moreover, foot beds can also be glued in place. In an aspect of the invention the waterproof gasket material can serve as a foot bed. For example, the waterproof gasket material may comprise a material which provides the necessary waterproofness as well as the desired comfort to the wearer. Ethylene vinyl acetate is particularly well suited for this aspect of the invention.

[0025] Of course, any suitable outer sole material can be attached to the bottom, outer portion of the closed upper.

[0026] In a further aspect of the invention it may be desirable to provide the outer layer material with selectively located decorative or functional materials to complete the footwear article. For example, in the case of sports shoes it may be desirable to add heel counters (made from, for example, thermoplastic polyurethane) to reduce over pronation. Further, a rubber toe cap can be provided to provide the toe area with extra protection. Moreover, simply decorative materials can be selectively located on the outer layer material to improve the visual appearance of the footwear. Such selectively located decorative or functional materials can be attached to the outer layer material in any suitable manner (e.g., adhesive, sewn, etc.). If the material is sewn to the outer layer material care should be taken to insure that waterproofness is not compromised (i.e., waterproof tape material or other sealant should be applied to cover any holes created by the stitching).

[0027] What is meant by “Waterproof footwear” is determined as follows. The footwear is placed on top of a piece of blotter paper. The inside of the footwear is filled with room temperature water to a height of about 30 mm (measured from the insole at the heel area of the footwear). The water is allowed to stand in the footwear for two hours. At the end of the two hour period the blotter paper and footwear upper are examined to determine if water has reached the blotter paper or the outer layer of the upper. If no water has reached the blotter paper or the the outer layer of the upper, then the footwear is waterproof.

[0028] As used herein the “waterproof, water vapor permeable functional layer” and the “waterproof gasket material” are “waterproof” if, when combined to form the footwear according to the invention, they result in the footwear being “waterproof” as defined above.

[0029] While particular embodiments of the present invention have been illustrated and described herein, the present invention should not be limited to such illustrations and descriptions. It should be apparent that changes and modifications may be incorporated and embodied as part of the present invention within the scope of the following claims. 

What is claimed is:
 1. Waterproof footwear comprising: a laminate upper having at least a waterproof, water vapor permeable functional layer and an outer layer stitched to a strobel board, forming a closed upper having an inner surface, an outer surface, an open top, and a closed bottom; and a waterproof gasket material adhered to the inner surface of the closed bottom of the closed upper.
 2. The waterproof footwear of claim 1, wherein an outer sole is attached to the outer surface of the closed bottom of the closed upper.
 3. The waterproof footwear of claim 1, wherein the waterproof gasket material is adhered to the closed bottom of the closed upper utilizing an adhesive material selected from the group consisting of polyurethane, natural latex rubber, nitrile rubber, silicone rubber, butyl rubber, fluorinated rubber, copolyether polyester, polyester, ethylene vinyl acetate, and polyamide.
 4. The waterproof footwear of claim 1, wherein the inner surface of the closed upper is further provided with an inner liner material.
 5. The waterproof footwear of claim 4, wherein the inner liner material comprises at least a textile material selected from the group consisting of woven, knit, mesh, non-woven, and felt constructions.
 6. The waterproof footwear of claim 5, wherein the textile fabric comprises at least a material selected from the group consisting of cotton, polyesters, polyamides, polypropylenes, polyolefins, and blends thereof.
 7. The waterproof footwear of claim 1, wherein the waterproof, water vapor permeable functional layer of the laminate upper comprises at least a polymeric membrane.
 8. The waterproof footwear of claim 7, wherein the polymeric membrane is selected from the group consisting of fluoropolymers, polyurethanes, polyesters, polyethers, polyamides, polyacrylates, copolyether esters, and copolyether amides.
 9. The waterproof footwear of claim 8, wherein the fluoropolymer is expanded polytetrafluoroethylene.
 10. The waterproof footwear of claim 1, wherein the outer layer of the laminate upper comprises leather.
 11. The waterproof footwear of claim 1, wherein the outer layer of the laminate upper comprises a textile fabric selected from the group consisting of woven, knit, mesh, non-woven, and felt constructions.
 12. The waterproof footwear of claim 11, wherein the textile fabric comprises a material selected from the group consisting of cotton, polyesters, polyamides, polypropylenes, polyolefins, and blends thereof.
 13. The waterproof footwear of claim 1, wherein the waterproof gasket material is a material selected from the group consisting of polymeric containing material, waterproof fabric, and textile material treated to make it waterproof.
 14. Method for making waterproof footwear comprising: stitching to a strobel board a laminate upper having at least a waterproof, water vapor permeable functional layer and an outer layer to form a closed upper having an inner surface, an outer surface, an open top, and a closed bottom; and adhereing a waterproof gasket material to the inner surface of the closed bottom of the closed upper.
 15. The method of claim 14, wherein an outer sole is attached to the outer surface of the closed bottom of the closed upper.
 16. The method of claim 14, wherein the waterproof gasket material is adhered to the closed bottom of the closed upper utilizing an adhesive material selected from the group consisting of polyurethane, natural latex rubber, nitrile rubber, silicone rubber, butyl rubber, fluorinated rubber, copolyether polyester, polyester, ethylene vinyl acetate, and polyamide.
 17. The method of claim 14, wherein an inner liner material is is attached to the inner surface of the closed upper.
 18. The method of claim 17, wherein the inner liner material comprises at least a textile material selected from the group consisting of woven, knit, mesh, non-woven, and felt constructions.
 19. The method of claim 18, wherein the textile fabric comprises at least a material selected from the group consisting of cotton, polyesters, polyamides, polypropylenes, polyolefins, and blends thereof.
 20. The method of claim 14, wherein the waterproof, water vapor permeable functional layer of the laminate upper comprises at least a polymeric membrane.
 21. The method of claim 20, wherein the polymeric membrane is selected from the group consisting of fluoropolymers, polyurethanes, polyesters, polyethers, polyamides, polyacrylates, copolyether esters, and copolyether amides.
 22. The method of claim 21, wherein the fluoropolymer is expanded polytetrafluoroethylene.
 23. The method of claim 14, wherein the outer layer of the laminate upper comprises leather.
 24. The method of claim 14, wherein the outer layer of the laminate upper comprises a textile fabric selected from the group consisting of woven, knit, mesh, non-woven, and felt constructions.
 25. The method of claim 24, wherein the textile fabric comprises a material selected from the group consisting of cotton, polyesters, polyamides, polypropylenes, polyolefins, and blends thereof.
 26. The method of claim 14, wherein the waterproof gasket material is a material selected from the group consisting of polymeric containing material, waterproof fabric, and textile material treated to make it waterproof. 